The Electrologica X1 and X8 computers

The X1 computer was conceived in 1958 at the Mathematical Centre
in Amsterdam, and commercially produced by Electrologica NV in The
Hague, a company specially established for this purpose, and the
first of its sort in the Netherlands (Philips was not interested in
building computers at the time). It has been successful - at least
31 machines were sold, many of them to other European countries.
The X1's successor was the X8 (1965), also a well-designed and
successful machine. The Electrologica story ended in 1966 when the
company was taken over by Philips, its main components producer
(IBM being another important Philips customer for computer
components....).

The basic X1 machine, fitting in a large writing desk (see
illustration) consisted of an arithmetic unit and several
registers, in particular two 27-bits accumulators A and S, a
condition register, an instruction register, and an index register.
A and S could be used together as a single double-length register
for multiply and divide operations. The basic machine had a
built-in 'live' (i.e. random-access) memory of 512 words of 28 bits
(including 1 sign bit and 1 parity bit); and 700 words of 'dead'
(i.e. read-only) memory. More memory could be added in separate
storage cabinets, up to 32768 (2^15) words, including additional
read-only memory. Normally there was no magnetic drum, disk or
other type of secondary memory (a magnetic drum was an optional
extension, however) . The interaction of the operator with the
machine was mainly by means of the console lights, switches and
audible alarms.

An X1 backplane with plug-in modules, and a folio-sized binder with the modules' schematics. Lower left corner: one of the modules, without sealing and cover. The Philips OC47 germanium transistors are clearly visible. Collection UvA Computer Museum, donated by Mr. F.A.M. Korst.

The X1 was completely transistorized ('as transistors do not produce any heat, no cooling apparatus is necessary', according to a sales brochure). The memory, both RAM and ROM, used ferrite cores. The number representation was binary, which was, in the late 50's, not the obvious choice for machines mainly intended for administrative applications - more often, binary coded decimal was used.

This is the control room of the Grande Dixence project in the vicinity of Zermatt, Switzerland. The complex problem of
managing this large distributed hydropower system was tackled by deploying an Electrologica X8 computer system. Photograph by courtesy of Mr. J.A. Th. M. van Berckel.

The X8 was much faster than its predecessor, the X1:

35 microsec per fixed-point multiplication or division

60 microsec per (hard-wired) floating point multiplication or division

memory cycle time 2.5 microsec.

An interesting feature was the use of a separate, independent peripheral processor ('CHARON') which handled the communication
between the X8 proper and magnetic tape, drum memory, punched tape and punched card, and telecom equipment. Algol, Fortran and Cobol compilers came with the standard package.

The X8 at the Mathematical Centre has been in service until 1972, when it was replaced by the Control Data Cyber 6500 mainframe of the SARA academic computer centre in Amsterdam. Another X8 was located at the Institute for Nuclear Physics (IKO) in Amsterdam, where it was used with the BOL project.

Only a few pieces of Electrologica-related hardware are in our collection, among which the Friden Flexowriter, used as a terminal for the X1 and X8. We have, though, a fair amount of documentation and other printed documents.